Exploring Polymer Classification in Litter Found in Lake Tahoe
In this brief segment from my full-length conversation with Monica Arienzo, who was the lead author of this study, she discusses whether there was a correlation between the different types of litter and the polymer type.
In this 2023 interview with Monica Arienzo of the Desert Research Institute, we highlighted her research exploring polymers are in different types of litter, and how each type impacts the environment (1).
In this brief segment from my full-length conversation with Arienzo, who was the lead author of this study, she discusses whether there was a correlation between the different types of litter and the polymer type.
Will Wetzel: Would you be able to describe the correlation that existed between the litter categories and the polymer type? Does a correlation exist relative to the global polymer production?
Arienzo: We took this litter, we sorted it into these item types, and then we collected these subsamples for attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy, and what we were interested in seeing is if these correlations existed. We found that nine litter type categories were comprised primarily of a single polymer. And some of this is going to seem obvious, but it was good for us to demonstrate this from the data. So, for plastic bottles, we found that they were dominated by polyethylene terephthalate (PT). Not surprising, right? This is what we know plastic bottles are made of for fishing gear, cutlery, and drink package rings. The primary plastic type was polystyrene. And again, we weren't surprised to see that, because this is what we know. We had thought that that's what these materials were made of.
It was similar for the monofilament line. Unsurprisingly, for that category, we found that the primary plastic type was polyamide, and then for the mesh bags litter type category, we found that those were made of polyethylene, and then for and then for baskets and crates, for that category, we found that those were made of pet polyethylene terephthalate. And then for plastic bags, we found that polyethylene comprised about 57% of those subsamples. And so, this is sort of what we expected to see. But as I mentioned, it was kind of good to demonstrate that by applying ATR to this litter that we had collected. To get to your question about correlation to global polymer production, the top five litter categories that we identified in our litter were made of polyvinyl chloride, polystyrene, polyethylene terephthalate, polyethylene, and polypropylene, and these have been previously shown to be very commonly produced plastics and some of the most commonly produced plastics. So yes, we saw a correlation with the most commonly identified plastic types in our study to what we would expect to see based on global plastic production trends.
You can see the study and my full-length video interview with Arienzo in references (1,2).
References
- Wetzel, W. Polymer Characterization of Plastic Litter Using ATR-FT-IR Spectroscopy: An Interview with Monica Arienzo. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/polymer-characterization-of-plastic-litter-using-atr-ft-ir-spectroscopy-an-interview-with-monica-arienzo (accessed 2025-04-15).
- Davidson, J.; Arienzo, M. M.; Harrold, Z.; West, C.; Bandala, E. R.; Easler, S.; Senft, K. Polymer Characterization of Submerged Plastic Litter from Lake Tahoe, United States. Appl. Spectrosc. 2023, ASAP. DOI: 10.1177/00037028231201174
